Previous efforts toward preparing multicellular aggregates (spheroids) have been made in
traditional rocker-plate [1], porous foam block [2], and microarray chip cultures [3] in order to maintain liver-specific functions in vitro. These approaches all employ static culture methods and thus physiological flow conditions could not be simulated. Furthermore, the ability to analyze cell viability and function in a high-throughput manner is hindered due to the opaque substrates used in all three systems. To effectively coalesce otherwise monolayer liver cells seeded into microfluidic channels,we present a high-density hepatic spheroid trapping array chip for rapid three-dimensional spheroid self-assembly. Microfabricated 3-D bioreactors address many of the issues associated with traditional liver cell culture such as providing more in vivo-like spatial cell-cell interactions [4]. A platform that closely mimics the in vivo architecture of the human liver has yet to be achieved. We aim to bring hepatic spheroid culture one-step closer to the realization of this goal.